NEW YORK (Reuters Health) - Patients with type 2 diabetes who also have liver cirrhosis due to hepatitis C virus (HCV) infection fare significantly better when they're treated with metformin, results of a French study indicate.

"Metformin treatment was independently associated with a decrease in HCC (hepatocellular carcinoma) occurrence and with a decreased rate of liver-related death," the researchers report in the August Journal of Clinical Endocrinology and Metabolism.

The authors point out that type 2 diabetes and hyperinsulinemia are common in patients with HCV cirrhosis, and there's evidence that insulin resistance plays a role in the development of liver cancer. Therefore, treatment with metformin could be beneficial in this setting.

To investigate, Dr. Emmanuel Cosson, with Hopital Jean Verdier in Bondy, and colleagues studied 100 patients with compensated HCV cirrhosis and type 2 diabetes, including 26 who took metformin.

Over a median of 5.7 years, 39 patients developed HCC and 33 either died of liver-related causes or had a liver transplant.

The team found that the five-year rate of HCC was 9.5% in metformin-treated patients vs 31.2% in patients who didn't take the drug. On multivariate analysis, metformin was independently associated with reduced risk of HCC (hazard ratio 0.19, p=0.023).

Similarly, the corresponding rate of death or transplantation was 5.9% vs. 17.4% in the two groups, respectively. This translated to an adjusted hazard ratio for death/transplantation of 0.22 (p=0.049), Dr. Cosson and colleagues report.

They note that this was an observational study, so cause and effect cannot be determined. "However, our findings add to the increasing body of evidence and may justify the initiation of clinical trials evaluating metformin in patients with hyperinsulinemia and HCV cirrhosis," they conclude.